i can answer this being a BSc in zoology its the egg because dinosaurs and reptiles laid them before birds were around! there are some intetresting things going on in evolutionary sceince and we have only touched the tip the the iceburg. my fav fact is that of all the species on earth we have only given names to 1 million. It is Conservatively estimated that there are 14 million we havent even named! i saw a video of a professor in the rain forest going up to a tree, put some paper underneth, shook the tree. he examined the paper and all he was saying was "new species, new species, never seen that before..." makes you think